1. Field of the Invention
This invention relates to an electron-emitting device, an electron source using the electron-emitting device, and an image forming apparatus.
2. Related Background Art
Conventionally, as an electron-emitting device, generally two kinds respectively using a thermionic cathode and a cold cathode are known. As the cold cathode, there is a field emission type (hereinafter referred to as an FE type), a metal/insulation layer/metal type (hereinafter referred to as an MIM type), a surface conduction type electron-emitting device or the like. As examples of the FE type, those which have been disclosed in W. P. Dyke & W. W. Dolan, “Field emission”, Advance in Electron Physics, 8,89 (1956) or C. A. Spindt. “Physical Properties of thin-film field emission cathodes with molybdenium cones”, J. Appl. Phys., 47.5248 (1976), etc. are known.
As examples of the MIM type, those which are disclosed in C. A. Mead“, Operation of Tunnel-Emission Devices”, J Apply. Phys. 32, 646 (1961), etc. are known.
As examples for the surface conduction type electron-emitting device, there are those which have been disclosed in M. I. Elinson, Radio Eng. Electron Phys, 10, 1290, (1965), etc.
The surface conduction type electron-emitting device is to utilize phenomena giving rise to the electron emission by making a current flow in parallel with the film surface at a small area of a film formed on a substrate. For this surface conduction type electron-emitting device, the one utilizing SnO2 film by aforementioned Elinson et al., the one involving Au film (G. Ditmmer, Thin Solid Films, 9.317(1972)), the one involving In2O3/SnO2 film (M. Hartwell and C. G. Fonsted, IEEE Trans. ED Conf., 519 (1975)), and the one involving carbon film (Hisashi Araki, et al., Vacuum, vol. 26, the first issue, page 22 (1983)), etc. have been reported.
The present applicant has presented a number of proposals on surface conduction type electron-emitting devices having novel configurations and their applications. Its basic configuration and manufacturing method, etc. have been disclosed in for example Japanese Patent Application Laid-Open No. 7-235255, Japanese Patent No. 2836015, Japanese Patent No. 2903295, etc.
Now, their points are briefly described below.
An example of surface conduction type electron-emitting device disclosed in the above-described publication is schematically shown in FIGS. 5A and 5B. As in FIGS. 5A and 5B, the device is configured to comprise a pair of device electrodes 2 and 3 facing each other on the substrate 1, and conductive film 4 which is connected with the device electrodes and has an electron-emitting region 5 in a part thereof. FIG. 5A is its schematic plan view, and FIG. 5B is its schematic sectional view. The electron-emitting region 5 is a portion where a part of the conductive film 4 has been destroyed, deformed, or changed in quality. And the electron-emitting region has a fissure. On the substrate 1 inside the fissure and on its adjacent conductive film 4, the deposit comprising carbon and/or carbon compound as main ingredients has been formed with a step called activation process.